a) Populations 



The electrofishing data indicated that the game fish populations of the 

 Mount Haggin streams are heavily dominated by brook trout. Brook trout are 

 the most abundant trout in the upper Big Hole River and the majority of its 

 tributaries (MDFWP unpublished data). A look at past stocking records shows 

 that despite numerous plantings of cutthroat and rainbow trout in Deep, 

 Seymour, Tenmile and Willow Creeks, the brook trout has emerged as the 

 strongest competitor in the habitat. This may be related to the brook trout's 

 tolerance of low summer flows in small streams (Wipperman, 1966, 1967 and 

 1968), adaptability to streams that are heavily colonized by beaver or the 

 harsh winter conditions of the area. In study sections for which it was 

 possible to calculate estimates of rainbow or cutthroat trout in addition to 

 brook trout, brook trout populations accounted for 81 to 95 percent of the 

 estimated trout numbers and 82 to 93 percent of the estimated trout biomass. 



Trout numbers generally ranged from good to excellent. Trout population 

 averaged 329 per 1,000 feet in the Mount Haggin streams and exceeded 500 per 

 1,000 feet in Seymour, Sullivan and Willow Creeks. Trout numbers did not 

 appear to be linked to stream size or the chemical enrichment of the water. 

 Some of the chemically sterile streams (e.g. Sixmile and Oregon Creeks) 

 supported 412 and 265 fish/1,000 feet while the two largest streams studied 

 (Deep and California Creeks) supported 184 and 160 fish/1,000 feet. 



Estimated trout populations were lowest in American and California 

 Creeks. Furthermore, trout numbers in French Creek (30 fish/1,000 ft) and 

 Deep Creek below the mouth of French Creek (34 fish/1,000 ft) were too low 

 to calculate an estimate in a 1979 study (MDFWP unpublished data). The 

 low numbers in American Creek were probably a function of the study section 

 that was electrof ished. Due to the presence of multiple channels and 

 numerous beaver ponds, the study section had to be located in an area of 

 steep gradient and swift currents. The population estimate for this section 

 probably does not accurately reflect the carrying capacity of American Creek 

 since large numbers of brook trout were observed in the small channels and 

 beaver ponds immediately upstream. The low numbers of fish in California, 

 French and Deep Creek below the mouth of French Creek are not as easily 

 explained. Water quality data indicated potential problems with arsenic, 

 lead, mercury, sediment and iron in sections of the California Creek-French 

 Creek drainage. While none of these parameters exceeded EPA water quality 

 standards in the grab samples, it is possible that one or a combination of 

 these factors is acting to depress fish population throughout the system. 

 The low fish populations may also be a result of habitat degredation from 

 past grazing practices along these streams. California and French creeks 

 exhibit many areas of eroded banks and a general deficiency of overhanging 

 cover from streamside vegetation due to heavy concentration of cattle within 

 the drainages. Bowers et al. (1979) considered stable streambank and adequate 

 streamside vegetation as essential components of good trout habitat in streams. 



b) Fish Size 



The data from the study sections indicated that the Mount Haggin 

 streams hold large populations of relatively small or "pan sized" trout. 



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